An expert is a man who has made all the mistakes, which can be made, in a very narrow field.
Such is the common process of marriage. A youth and maiden exchange meeting by chance, or brought together by artifice, exchange glances, reciprocate civilities, go home, and dream of one another. Having little to divert attention, or diversify thought, they find themselves uneasy when they are apart, and therefore conclude that they shall be happy together. They marry, and discover what nothing but voluntary blindness had before concealed they wear out life in altercations, and charge nature with cruelty.
Insist on yourself never imitate. Your own gift you can present every moment with the cumulative force of a whole life's cultivation but of the adopted talent of another you have only an extemporaneous half possession... Do that which is assigned to you, and you cannot hope too much or dare too much.
One of the great liabilities of history is that all too many people fail to remain awake through great periods of social change. Every society has its protectors of status quo and its fraternities of the indifferent who are notorious for sleeping through revolutions. Today, our very survival depends on our ability to stay awake, to adjust to new ideas, to remain vigilant and to face the challenge of change.